Effects of Milling on Surface Integrity and Fatigue Performance of TC4 Titanium Alloy by SLM.

Aiming at the problems of poor surface quality and low fatigue performance of TC4 titanium alloys by SLM, the influences of the milling processes on the surface integrity and fatigue performance of the additive parts were studied by three-point bending fatigue tests of additive parts before and after milling. The results show that after milling, the surface roughness Ra of the additive parts is reduced from 12.57 µm to 0.32 µm, the surface hardness is increased from 353.0HV to 434.3HV, fatigue life of additive parts is increased from 48 272 cycles to 155 463 cycles. After milling, the location of fatigue source of additive parts is transferred from the surface and subsurface to the interior of the specimen, and the fatigue fracture mode is changed from quasi-dissolution fracture to ductile fracture. The surface integrity of the milled specimens is greatly improved, the fatigue crack emergence and expansion of surface fatigue cracks are suppressed, and the fatigue performance is significantly improved after milling of the additive parts. [ABSTRACT FROM AUTHOR]